This project is concerned with the study of muscle biochemistry using cultured rat heart cells as the tool. The main objectives of this proposed work this year are: (1) to examine the biochemical events occurring in the time immediately after heart tissue is dissociated for culturing and the time the cells attach to the Petri dishes and begin to beat, (2) to determine the effects of anesthestics on the beating heart cells and to decide whether they affect mainly the energy production or energy requiring processes in cardiac cells, (3) to examine myosin heavy chains and light chains from cells in young cultures and cells in older cultures and (4) to measure cyclic AMP concentration in cells treated with various anesthetics and drugs. BIBLIOGRAPHIC REFERENCES: L.J. Stong, C.H. Hartzell, and R.L. McCarl. Effects of Halothane on the Beating Response and ATP Turnover Rate of Heart Cells in Tissue Culture. Anesthesiology, 42, 123-132 (1975).